This leaks some of the internal details like `AutoNoTable` to the end user. Instead I would suggest something like the following for this section. (Wrap at 79):
```
Set the calculation mode for formulas in the workbook. This is mainly of use
for workbooks with slow formulas where you want to allow the user to
calculate them manually.

The ``mode`` parameter can be:

* ``auto``: The default. Excel will re-calculate formulas when a formula or 
  a value affecting the formula changes.

* ``auto_except_tables``: Excel will automatically re-calculate formulas
  except for tables.

* ``manual``: Only re-calculate formulas when the user requires it. Generally
  by pressing F9.
```